Telegraph transmitter



July 25, 1939. R. D. SALMON 2,167,5 8

TELEGRAPH TRANSMITTER Filed March 20, 1936 2 Sheets-Sheet 1 Fig. J

ATTORNEY July 25, 1939. R. D. SALMON TELEGRAPH TRANSMITTER Filed March 20, 1936 2 Sheets-Sheet 2 3y SIQAMO/V Patented July 25, 1939 UNITED STATES PATENT OFFICE TELEGRAPH TRANSMITTER- don, Surrey, England Application March 20,

1936, Serial No. 69,772

In Great Britain April 5, 1935 8 Claims.

This invention relates to telegraph transmitters of the kind in which signal controlling means such as a key determine the successive operation of a single transmitting contact tongue in accordance with the elements of a signal.

In one class of such transmitters selector levers are selectively moved so as to be acted upon by a series of cams to cause movement of the contact tongue. In another class of such transmitters selector levers are invariably acted upon by a series of cams but are selectively rendered operative upon the contact tongue.

It has also been proposed to form the cam that acts on the contact tongue as a series of slidable bars that are selectively withdrawn, the ends of the bars that are not withdrawn moving the transmitting contact tongue and holding it during the whole signal element period.

In all the above constructions, the accuracy of the timing of the duration of a signal element depends upon the accuracy of a number of dimensions of the apparatus, and all these dimensions have to be determined within rather fine limits if the signals are not to be inaccurate to a degree that is not permissible. Moreover, the length of the signal element does not depend upon a positive action of the transmitting cam in both directions, for the transit in one direction at least depends upon spring action.

According to one feature of this invention I provide a telegraph transmitter of the kind referred to in which every transit of the transmitting contact tongue is determined by positive cam action.

According to another feature of this invention I provide a telegraph transmitter of the kind referred to in which a selector lever moved by means of a key or the like according to the character of a signal element to be transmitted is effective to determine the position of the transmitting contact tongue during a brief portion only of each signal element period.

According to another feature of the invention I provide a telegraph transmitter of the kind referred to comprising a selector lever adapted to be moved according to the character of a signal element to be transmitted, a cam for determining the duration of the signal element, and an intermediate lever adapted to be struck by the cam to cause the selector lever to position the transmitting contact tongue according to the position of the selector lever.

The arrangements according to the invention may be looked upon from one point of View as constituting a telegraph transmitter of the kind referred to in which the duration of the signal elements is determined by means which are known as applied to the regeneration of received signals. In applying these arrangements to a transmitter controlled by means such as a key, the setting of a selector lever by the signal controlling means such as a key is treated as if it were due to a received signal element. By this means I achieve with a transmitter the high degree of accuracy in the transmitted signals that can be obtained with this form of regenerator which has not hitherto been obtained with an original transmitter and at the same time the extreme accuracy of manufacture is confined to a very few parts.

The invention will be better understood from the following description taken in conjunction with the accompanying drawings in which Fig. 1 shows diagrammatically the principle of the invention;

Fig. 2 shows in perspective a practical form of transmitter embodying the invention with certain parts omitted for the sake of clearness;

Fig. 3 is a View in vertical cross section of the transmitter of Fig. 2, showing one of the selector levers and associated mechanism, and

Fig. 4 is another vertical cross section showing the arrangements for starting and stopping the cam spindle.

In Fig. l is shown a keyboard transmitter for sending signals on a start stop system comprising six combination bars CB (one only of which is shown), one moved invariably by the depression of any key and the other live moved in combinations according to the key depressed.

The ends of these bars CB selectively move into the path of selector levers SL which are allowed to be moved successively by their individual springs by hollows in a rotating cam sleeve SC. These selector levers SL control against the action of a returning spring, a shuttle bar A which moves an intermediate lever B to right or left. This lever B is formed with a knife edge D at one extremity and is struck against a knife edge D on the transmitting contact tongue C once for each signal element to be transmitted by means of a cam F on the same shaft as cam sleeve SC. The transmitting contact tongue C is moved to one side or the other according to the position of the intermediate lever B at the movement of contact A locking bar LB controlled by a cam may be provided in the usual manner for holding the combination bars CB in position.

It will be seen that the combination bars CB and selector levers SL are positioned according to the transmitter described in British Patent No. 264,907. To this is added a form of regenerator mechanism known per se consisting of the cam SC, intermediate lever B, and transmitting contact tongue but it is now only necessary that accuracy of manufacture and assembly should be exercised in these latter parts.

Referring now to Figs. 2, 3 and 4 which show the preferred manner of performing the invention, the transmitting cam spindle I carries seven cams 6 co-operating with seven intermediate levers 5 which also co-operate with seven selecting arms 4. Each arm 4 is carried at one end of a two-armed lever 8 engaging at its other end combination bar 9 which is under the control of the keybars which are not shown. The selecting arms 4 are arranged to co-operate with two rocking frames 3 carrying two lever arms 2 which carry at their topmost ends a link I which engages with the transmitting contact lever ZI.

The transmitting spindle l is normally driven by a friction clutch, and is held stationary by means of a detent I2 engaging with a stop arm II). The other arm II of the stop arm I0 is under the control of a resetting cam I3, and also co-operates with a stop M. The stop I6 is engaged by a latch I5 carried by a bellcrank lever I6 which also engages with the trip bar H, which is also under the control of the keybars not shown.

Upon the depression of any key the trip bar I! is moved to the left and the combination bars 9 are set in accordance with the keybar which has been depressed. The movement of the trip bar I? rotates the bellcrank I6, thereby pulling the latch I5 downwards, thereby rotating the stop I4 against the action of its spring 23 in a clockwise direction. The movement of the stop I4 releases the stop arm I0, thereby permitting it to be withdrawn from engagement with the detent I2 under the action of its spring 22, thereby releasing the transmitting spindle 'I, and permitting it to rotate under the action of its driving clutch. The movement of the detent also acts to disengage the latch I 5 from the stop I4, thereby permitting the stop I to be partially reset under the action of its spring 23 so that if the keybar is held down permanently it will not prevent the transmitting cam spindle I from being arrested at the end of its revolution. As the transmitting cam rotates, the reset cam I3 comes up against the projection on the resetting lever II, thereby rotating the stop arm II? in an anticlockwise direction, and moving the end of the resetting lever II out of engagement with the stop I4, thereby permitting the stop I4 to be moved into its initial position under the action of its spring 23 so as to hold the resetting lever I I, and consequently the stop arm Ill in such a position that when the transmitting cam I completes its revolution it will be arrested. By this means the force required to release the transmitting cam is reduced to a minimum, as the strength of the spring 23 which holds the stop I4 in position is extremely light, and the pressure of the resetting arm II against the stop I4 is also very light.

It is a' feature of this invention that the stop arm that engages the detent holding the transmitting cam spindle stationary is not directly linked to the universal bar but is held by means of a pivoted stop, withdrawn by the movement of the universal bar.

The setting of the combination bars 9 through the medium of the two arm levers 8 moves the arms 4 in a righthand or lefthand position. As the transmitting cam rotates, the intermediate levers 5 are lifted seriatim, thereby striking the arms 4 against one or other of the rocking frames 3, and consequently moving the link I in one direction or the other. The movement of the link I moves the transmitting contact arm 2|, which is held in one position or the other by means of a jockey device (not shown).

By employing the intermediate levers 5 the time of transit of the transmitting contact tongue may be determined very accurately. The selector levers 4 must be shaped, on the side towards the cams 6, in such a way as to allow free to and fro movement, but each intermediate lever 5, since it is not movable horizontally, is formed with a depending nose as shown so that the time at which it is struck by its cam is sharply defined.

All the levers 5 are carried upon a spindle 24 which is carried upon plates 20 that are adjustable with respect to the axis of the cam spindle i, and the rocking arms 3 are carried upon spindle 25 which are carried upon plates I9 which are also adjustable with respect to the cam spindle i. By this means the axes of the intermediate lever pivots and the rocking arm pivots and the cam spindle, can all be made parallel with one another. Furthermore, the intermedi ate levers can be made exactly similar to one another within a high degree of accuracy, as also can the arms 4. By this means the timing of the transmitted signal elements can be maintained within a high degree of accuracy, without difficult manufacture.

What is claimed is:

1. In a telegraph transmitter, a transmitting contact tongue, a selector lever movable in accordance with the character of the signal element to be transmitted for positioning said transmitting contact tongue, and means operative upon said selector lever only during a brief interval of time during receipt of said signal element to position said contact tongue.

2. A telegraph transmitter of the kind referred to comprising, a transmitting contact tongue, a selector lever operatively associated with said transmitting contact tongue, means for moving said selector lever in accordance with the character of a signal element to be transmitted, a cam for determining the duration of the signal element, an intermediate lever mounted between said cam and said selector lever, to cause said selector lever to position said transmitting contact tongue according to the position of the selector lever, and means for holding said transmitting contact tongue in the position into which it was last moved.

3. A telegraph transmitter of the kind referred to comprising, a transmitting contact tongue, a series of selector levers, one for each signal element, operatively associated with said transmitting contact tongue, means for positioning said selector levers in accordance with the character of the respective signal elements, a series of cams for determining the duration of the respective signalling elements, a series of intermediate levers, each positioned to be struck by one of said cams and to strike its corresponding selector lever to cause the latter to position the transmitting contact tongue, and means for holding the transmitting contact tongue in the position into which it was last moved.

4. A telegraph transmitter as claimed in claim 3 in which the intermediate lever, is formed with a nose adapted to be struck by a cam.

5. A telegraph transmitter as claimed in claim 3, further comprising a rocking frame formed with a fork for actuation of the transmitting contact tongue cooperating with said selector lever.

6. A telegraph transmitter as claimed in claim 3, further comprising a common rod upon which 10 all said intermediate levers are pivoted.

'7. A telegraph transmitter as claimed in claim 3, further comprising a rod upon which all the said intermediate levers are pivoted, and plates adjustably mounted on the transmitter for supporting said rods.

8. A telegraph transmitter as claimed in claim 2,'further comprising plates adjustably mounted on said transmitter, and a rocking frame for actuating said transmitting contact tongue pivoted in said plates.

REGINALD DENNIS SALMON. 

